The proposed research aims to determine the degree to which conformational fluctuations of galactose/glucose binding protein (GBP) influence its function. Conformationally-sensitive single molecule fluorescence and bulk measurements will determine the nature (discrete vs. continuous) of GBP states and the relative importance of conformational flexibility in the selective recognition of ligands by proteins. Another goal is to study the role of GBP conformations in the function of an glucose active-transport membrane-assembly. The training aspects of the plan include integration of and exposure to many techniques in molecular biology and chemical physics including mutant protein expression, bioconjugate preparation, microfluidics, and single molecule measurements, and analysis.